History ArchEnemy / Ben10

** Ben's greatest enemy of all is [[Characters/Ben10Vilgax Vilgax]], by virtue of being by far the oldest and most persistent, as well as having a direct connection to Ben's OriginStory, and appears in all series as an antagonist, which extends to the reboot, where he is treated as the most serious and dangerous threat to him of all. In fact, even when faced with the EldritchAbomination Dagon, Ben's main concern was Vilgax (who had been [[DemotedToDragon demoted to Dagon's herald]] but eventually [[TheStarscream usurped him]] and [[HijackingCthulhu absorbed his powers]]). Their rivalry proved so strong that Vilgax once hatched a plot to wipe out every version of Ben from the multiverse just to get back at him, with the resulting conquest protentional being a bonus to him.

** Zs'Skayr was the consciousness hidden within Ben's [[OurGhostsAreDifferent Ghostfreak]] transformation, serving as an EnemyWithout to Ben, even making afraid of the Ghostfreak transformation both before and after his escape, with the general intensity of their battles often putting Ben at the end of his rope, to the point he formed an EnemyMine with ''Vilgax'' to confront Zs'Skayr, and even then only won by trapping him back in the Omnitrix. By ''Omniverse'', Ben, in a deviation from his battle happy persona, was content to leave Zs'Skayr be on the Anur System rather than fight him until he had no choice.

* However, Gwen's biggest personal enemy was Hex's niece, Charmcaster, being more directly linked to her magical journey when Gwen stole her spell book during her second appearance, leading Charmcaster to hold a grudge over Gwen for being sorceress, with Gwen being her main target during the Negative 10 saga. When she returned for ''Alien Force'', Charmcaster's goal was to absorb Gwen's mana, and steal her boyfriend in an EvilIsPetty move, with an alternate timeline visited in one episode mentioning Charmcaster as having killed Gwen. During ''Ultimate Alien'', Charmcaster starts going through a HeelFaceRevolvingDoor, with Gwen trying to befriend her to redeem her, which continues into ''Omniverse'', where Gwen was PutOnABus, but still showed in Charmcaster's episodes.

** Ben's greatest enemy of all is [[Characters/Ben10Vilgax Vilgax]], by virtue of being by far the oldest and most persistent, as well as having a direct connection to Ben's OriginStory, and appears in all series as an antagonist, which extends to the reboot, where he is treated as the most serious and dangerous threat to him of all. In fact, even when faced with the EldritchAbomination Dagon, Ben's main concern was Vilgax (who had been [[DemotedToDragon demoted to Dagon's herald]] but eventually [[TheStarscream usurped him]] and absorbed his powers). Their rivaly proved so strong that Vilgax once hatched a plot to wipe out every version of Ben from the multiverse just to get back at him, with the resulting conquest protentional being a bonus to him.

** [[EvilCounterpart Kevin 11]] served as Ben's antithesis in their childhood, in the way he used his powers for his selfish desires and eventually mutated into a amalgamated form of Ben's original ten aliens, but made a HeelFaceTurn when they became teenagers, becoming best friends, with Ben even calling Kevin the brother he never had by "Ultimate Alien". He was replaced as Ben's antithesis by Albedo, Azmuth's former assistant trapped in the form of a [[EvilTwin color-inverted version]] of Ben, who is treated as more of a HarmlessVillain than Kevin was, though still attempting to prove his worth by the manner of being the creator of the Ultimatrix. When Kevin went insane again as "Ultimate Kevin" after being mutated by the Ultimatrix, Ben more or less spent the entire arc in crisis mode and was a lot quicker to use extreme tactics to take Kevin down than his other enemies, not just because a power enemy was on the attack, but because Ultimate Kevin was a personal failing he needed to correct.
** Zs'Skayr was the consciousness hidden within Ben's [[OurGhostsAreDifferent Ghostfreak]] transformation, serving as an EnemyWithout to Ben, even making afraid of the Ghostfreak transformation both before and after his escape, with the general intensity of their battles often putting Ben at the end of his rope, to the point he formed an EnemyMine with ''Vilgax'' to confront Zs'Skayr, and even then only won by trapping him back in the Omnitrix. By ''Omniverse'', Ben, in a deviation from his battle happy persona, was content to leave Zs'Skayr be on the Anur System rather than fight him until her had no choice.

** Zs'Skayr was the consciousness hidden within Ben's [[OurGhostsAreDifferent Ghostfreak]] transformation, serving as an EnemyWithout to Ben, even making afraid of the Ghostfreak transmornation both before and after his escape, with the general intensity of their battles often putting Ben at the end of his rope, to the point he formed an EnemyMine with ''Vilgax'' to confront Zs'Skayr, and even then only won by trapping him back in the Omnitrix. By ''Omniverse'', Ben, in a deviation from his battle happy persona, was content to leave Zs'Skayr be on the Anur System rather than fight him until her had no choice.

** Ben's greatest enemy of all is [[Characters/Ben10Vilgax Vilgax]], by virtue of being by far the oldest and most persistent, as well as having a direct connection to Ben's OriginStory, and appears in all series as an antagonist, which extends to the reboot where he is treated as the most serious and dangerous threat to him of all. In fact, even when faced with the EldritchAbomination Dagon, Ben's main concern was Vilgax (who had been [[DemotedToDragon demoted to Dagon's herald]] but eventually [[TheStarscream usurped him]] and absorbed his powers), but eventually. Aside from Vilgax, however, Ben's greatest enemies include;
** Zs'Skayr, the consciousness hidden within Ben's [[OurGhostsAreDifferent Ghostfreak]] transformation, served as one for the level of grudge he has with Ben as an EnemyWithout and the general intensity of their schemes and battles, to the point Ben formed an EnemyMine with ''Vilgax'' at one point to confront him.
** [[MadScientist Dr. Animo]], Ben's most recurring human enemy, who [[OvershadowedByAwesome ended up overshadowed by more dangerous foes]], but would remain a thorn in Ben's side until at least his 40s. In fact, when getting the Negative 10 to start infighting, Ben shows an uncharacteristic WorthyOpponent feeling toward Animo by feeling he should be "next in charge" of the group.
** [[EvilCounterpart Kevin 11]] served as Ben's antithesis in their childhood, in the way he used his powers for his selfish desires and eventually mutated into a hybrid form of Ben's aliens, but made a HeelFaceTurn when they became teenagers, becoming best friends, with Ben even calling Kevin the brother he never had by "Ultimate Alien". He was replaced as Ben's antithesis by Albedo, Azmuth's former assistant trapped in the form of a [[EvilTwin color-inverted version]] of Ben, who is treated as more of a HarmlessVillain than Kevin was, though still attempting to prove his worth by the manner of being the creator of the Ultimatrix. When Kevin went insane again and became even more dangerous than before as Ultimate Kevin, Ben more or less spent the entire period in crisis mode and was a lot quicker to use extreme tactics to take Kevin down no matter the costs as, not just a great villain returning, but a personal failing he needed to correct.
** The rogue Galvanic Mechamorph Malware would serve as another personal adversary for Ben, with Ben even fearing him due to him destroying Feedback, essentially killing a part of Ben and being implied to be the reason he removed the Omnitrix in the TimeSkip between series. Meanwhile, despite debuting in the lighter ''Omniverse'' series, neither Ben nor the narrative ever treat Malware or the threat he poses as a joke.

* Ben has many contenders to the title, but his greatest enemy of all is [[Characters/Ben10Vilgax Vilgax]], by virtue of being by far the oldest and most persistent, as well as having a direct connection to Ben's OriginStory, and appears in all series as an antagonist, which extends to the reboot where he is treated as the most serious and dangerous threat to him of all. In fact, even when faced with the EldritchAbomination Dagon, Ben's main concern was Vilgax (who had been [[DemotedToDragon demoted to Dagon's herald]] but eventually [[TheStarscream usurped him]] and absorbed his powers), but eventually. Aside from Vilgax, however, Ben's greatest enemies include;

** [[EvilCounterpart Kevin 11]] served as Ben's antithesis in their childhood, in the way he used his powers for his selfish desires and eventually mutated into a hybrid form of Ben's aliens, but made a HeelFaceTurn when they became teenagers, becoming best friends, with Ben even calling Kevin the brother he never had by "Ultimate Alien". He was replaced as Ben's antithesis by Albedo, Azmuth's former assistant trapped in the form of a [[EvilTwin color-inverted version]] of Ben, who is treated as more of a HarmlessVillain than Kevin was, though still attempting to prove his worth by the manner of being the creator of the Ultimatrix.
** The rogue Galvanic Mechamorph Malware would serve as another personal adversary for Ben, with Ben even fearing him due to him destroying Feedback, essentially killing a part of Ben and being implied to be the reason he removed the Omnitrix in the TimeSkip between series.
** The above competitors for the status as one of Ben's arch-enemies also vary greatly in how Ben treats them. Ben treats Animo more or less as a persistent but lower-tier villain by the events of ''Ultimate Alien'', but he does ''not'' extend this to Kevin or Malware: When Kevin went insane again and became even more dangerous than before as Ultimate Kevin, Ben more or less spent the entire period in crisis mode and was a lot quicker to use extreme tactics to take Kevin down no matter the costs as, not just a great villain returning, but a personal failing he needed to correct. Meanwhile, despite debuting in the lighter ''Omniverse'' series, neither Ben nor the narrative ever treat Malware or the threat he poses as a joke.

* After the events of "Dr. Animo and the Mutant Ray", Grandpa Max has a subtly rivalry with Dr. Animo, taking the Doctor's threat more seriously after being mutated by him, even getting noticeably violent towards Animo specifically during the Negative 10 saga. During ''Alien Force'', the two have a private war in the Null Void as the Wrench and D'Void. ''Omniverse'' even shows that the two will be at odds, though more as FriendlyEnemies, in the future.

* Rook Blonko has his former master Kundo, who hates Rook's use of technology and breaking of old Revonnahgander traditions by leaving Earth. Their conflict becomes truly personal when Rook finds out Kundo had injured his father while trying to stop his sister leaving Revonnah.

* Gwen started out with Hex, the villain of her ADayInTheLimelight episode that began her connection to magic with the Charms of Bezel, with his returning episode making it clear he desires revenge on "Lucky Girl" for his previous defeat and his final episode having him blame her alone for his downfall, completely overlooking Ben's part in his defeats, making him the only villain in the show to disregard Ben. During the TimeSkip, by the events of ''Ultimate Alien'', Hex fell into a depression that made him unwilling to fight Gwen even when she invaded his house, instead just asking her to leave him alone. He ends up undergoing a HeelFaceTurn by ''Omniverse;;, becoming a teacher at Gwen's university and the pair manage to bury the hatchet, with Gwen even calling Hex her favourite teacher.

* While Ragnarok appeared for only one episode, his link to Kevin's origin is enough to qualify as Kevin's Arch-enemy. In ''Omniverse'', Kevin gains a new recurring one in Proctor Servantis, another villain with major ties to Kevin's backstory [[spoiler:and who implanted false memories into Kevin and the Plumbers' kids to get them close to Ben, with the aforementioned Ragnarok ultimately turning out to be one of Servantis' allies]].

* Gwen started out with Hex, the villain of her ADayInTheLimelight episode that began her connection to magic with the Charms of Bezel, with his returning episode making it clear he desires revenge on "Lucky Girl" for his previous defeat and his final episode having him blame her alone for his downfall, completely overlooking Ben's part in his defeats, making him the only villain in the show to disregard Ben. During the TimeSkip, by the events of Western Animation/Ben10UltimateAlien, Hex fell into a depression that made him unwilling to fight Gwen even when she invaded his house, instead just asking her to leave him alone. He ends up undergoing a HeelFaceTurn by Western Animation/Ben10Omniverse, becoming a teacher at Gwen's university and the pair manage to bury the hatchet, with Gwen even calling Hex her favourite teacher.
* However, Gwen's biggest personal enemy was Hex's niece, Charmcaster, being more directly linked to her magical journey when Gwen stole her spell book during her second appearance, leading Charmcaster to hold a grudge over Gwen for being sorceress, with Gwen being her main target during the Negative 10 saga. When she returned for Western Animation/Ben10:AlienForce, Charmcaster's goal was to absorb Gwen's mana, and steal her boyfriend in an EvilIsPetty move, with an alternate timeline visited in one episode mentioning Charmcaster as having killed Gwen. During Ben10UltimateAlien, Charmcaster starts going through a HeelFaceRevolvingDoor in Western Animation/Ben10UltimateAlien, with Gwen trying to befriend her to redeem her, which continues into Western Animation/Ben10Omniverse, where Gwen was PutOnABus, but still showed in Charmcaster's episodes.

* However, Gwen's biggest personal enemy was Hex's niece, Charmcaster, being more directly linked to her magical journey when Gwen stole her spell book during her second appearance, leading Charmcaster to hold a grudge over Gwen for being sorceress, with Gwen being her main target during the Negative 10 saga. When she returned for Western Animation/Ben10AlienForce, Charmcaster's goal was to absorb Gwen's mana, and steal her boyfriend in an EvilIsPetty move, with an alternate timeline visited in one episode mentioning Charmcaster as having killed Gwen. During Ben10UltimateAlien, Charmcaster starts going through a HeelFaceRevolvingDoor in Western Animation/Ben10UltimateAlien, with Gwen trying to befriend her to redeem her, which continues into Western Animation/Ben10Omniverse, where Gwen was PutOnABus, but still showed in Charmcaster's episodes.

* Gwen started out with Hex, the villain of her ADayInTheLimelight episode that began her connection to magic with the Charms of Bezel, with his returning episode making it clear he desires revenge on "Lucky Girl" for his previous defeat and his final episode having him blame her alone for his downfall, completely overlooking Ben's part in his defeats, making him the only villain in the show to disregard Ben. During the TimeSkip, by the events of Ben10:UltimateAlien, Hex fell into a depression that made him unwilling to fight Gwen even when she invaded his house, instead just asking her to leave him alone. He ends up undergoing a HeelFaceTurn by Ben10:Omniverse, becoming a teacher at Gwen's university and the pair manage to bury the hatchet, with Gwen even calling Hex her favourite teacher.
* However, Gwen's biggest personal enemy was Hex's niece, Charmcaster, being more directly linked to her magical journey when Gwen stole her spell book during her second appearance, leading Charmcaster to hold a grudge over Gwen for being sorceress, with Gwen being her main target during the Negative 10 saga. When she returned for Ben10:AlienForce, Charmcaster's goal was to absorb Gwen's mana, and steal her boyfriend in an EvilIsPetty move, with an alternate timeline visited in one episode mentioning Charmcaster as having killed Gwen. During Ben10UltimateAlien, Charmcaster starts going through a HeelFaceRevolvingDoor in Ben10:UltimateAlien, with Gwen trying to befriend her to redeem her, which continues into Ben10:Omniverse, where Gwen was PutOnABus, but still showed in Charmcaster's episodes.

* Gwen started out with Hex, the villain of her ADayInTheLimelight episode that began her connection to magic with the Charms of Bezel, with his returning episode making it clear he desires revenge on "Lucky Girl" for his previous defeat and his final episode having him blame her alone for his downfall, completely overlooking Ben's part in his defeats, making him the only villain in the show to disregard Ben. During the TimeSkip, by the events of Ben10UltimateAlien, Hex fell into a depression that made him unwilling to fight Gwen even when she invaded his house, instead just asking her to leave him alone. He ends up undergoing a HeelFaceTurn by Ben10Omniverse, becoming a teacher at Gwen's university and the pair manage to bury the hatchet, with Gwen even calling Hex her favourite teacher.
* However, Gwen's biggest personal enemy was Hex's niece, Charmcaster, being more directly linked to her magical journey when Gwen stole her spell book during her second appearance, leading Charmcaster to hold a grudge over Gwen for being sorceress, with Gwen being her main target during the Negative 10 saga. When she returned for Ben10AlienForce, Charmcaster's goal was to absorb Gwen's mana, and steal her boyfriend in an EvilIsPetty move, with an alternate timeline visited in one episode mentioning Charmcaster as having killed Gwen. During Ben10UltimateAlien, Charmcaster starts going through a HeelFaceRevolvingDoor since ''Ultimate Alien'', with Gwen trying to befriend her to redeem her, which continues into Ben10Omniverse, where Gwen was PutOnABus, but still showed in Charmcaster's episodes.

* Ben has many contenders to the title, but his greatest enemy of all is [[Characters/Ben10Vilgax Vilgax]], by virtue of being by far the oldest and most persistent (he already was an ArchEnemy to Ben's ''grandfather''), as well as having a direct connection to Ben's OriginStory, and appears in all series as an antagonist, which extends to the reboot where he is treated as the most serious and dangerous threat to him of all. In fact, even when faced with the EldritchAbomination Dagon, Ben's main concern was Vilgax (who had been [[DemotedToDragon demoted to Dagon's herald]] but eventually [[TheStarscream usurped him]] and absorbed his powers), but eventually. Aside from Vilgax, however, Ben's greatest enemies include;

* Gwen Tennyson has Hex and Charmcaster, both being directly linked to her connection to magic. While both of them ''did'' fight Ben, it's pretty clear their grudge toward Gwen is much more personal. Hex ends up undergoing a HeelFaceTurn in ''Omniverse'', leaving Charmcaster as Gwen's sole main antagonist (Charmcaster herself has been going through the HeelFaceRevolvingDoor since ''Ultimate Alien'', but has performed enough villainous acts to still qualify).

* [[Characters/Ben10BenTennyson Ben Tennyson]] has many contenders to the title, but his greatest enemy of all is [[Characters/Ben10Vilgax Vilgax]], by virtue of being by far the oldest and most persistent (he already was an ArchEnemy to Ben's ''grandfather''), as well as having a direct connection to Ben's OriginStory, and appears in all series as an antagonist, which extends to the reboot where he is treated as the most serious and dangerous threat to him of all. In fact, even when faced with the EldritchAbomination Dagon, Ben's main concern was Vilgax (who had been [[DemotedToDragon demoted to Dagon's herald]] but eventually [[TheStarscream usurped him]] and absorbed his powers), but eventually. Aside from Vilgax, however, Ben's greatest enemies include;

* [[Characters/Ben10BenTennyson Ben Tennyson]] has many contenders to the title, but his greatest enemy of all is [[Characters/Ben10Vilgax Vilgax]], by virtue of being by far the oldest and most persistent (he already was an ArchEnemy to Ben's ''grandfather''), as well as having a direct connection to Ben's OriginStory, and appears in all series as an antagonist, which extends to the reboot where he is treated as the most serious and dangerous threat to him of all. In fact, even when faced with the EldritchAbomination Dagon, Ben's main concern was Vilgax. Aside from Vilgax, however, Ben's greatest enemies include;